Effect of nitrogen content, titanium content and prior deformation on creep behaviour of nitrided austenitic steels

Wear behaviour at 600°C of surface engineered low-alloy steel containing TiC particles

“…Despite (i) Marangonian forces redistributing the TiC particulates and precipitates, depending on the viscosity of the melt, and (ii) the centre region of the TIG arc generating more heat than the outer regions (this produced higher temperatures in the middle of the melt, which gave rise to a greater dissolution of the TiC particulates, resulting in more TiC precipitates during a longer cooling time), the arrowed inset in Figure 4 shows TiC precipitates in the form of globular and flower morphologies within the 1-mm deep multipass tracks. These and similar morphologies have been observed in titanium containing hot-rolled austenitic stainless steels [26] and in microalloyed steels [27,28] and are considered to originate during cooling from the casting process, which is in keeping with the present work. The lower density of the TiC particulate, 4.66 g cm −3 , calculated from the lattice parameter at 1727°C [29] compared to the low-alloy steel, 7.015 g cm −3 at 1536°C [30], resulted in the TiC floating and segregating near the surface, a view also expressed by Wang et al [31].…”

Ausscheidungsverhalten der hitzebeständigen austenitischen Gußstähle G‐X 40 CrNiSi 25 20, G‐X 40 NiCrSi 35 25 und G‐X 35 CrNiSiNb 24 24

“…(3,l--4,5) 800 34172 M6C 47, 9 4,6 34,3 (47,3--48,2) (3,6-6,0) (33, 9) 1100 912 M2(C,N) 84,5 4,7 0,4 (84-84, 8) (4,6-5,1) (0,3-0,6) 800 5684 a-Phase 42,7 41, 7 8,6 (41,l-43,6) ( 40, l -43,9) (8,0-9,3) 800 500 a-Phase 41,7 43, 8 9,6 (40,2-42,2) (42, 9) (9,l-10, 5) Dabei wurde davon ausgegangen, daB ein EinfluB einer Verformung auf die Ausscheidungsvorgiinge in den Einspannki:ipfen vemachlassigt werden darf. Nachdem die Umwandlung M 7 C 3 -+ M 23 C 6 eingesetzt hat, wandelt sich ein Tei!…”